Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

THE BAADER BBHS-SITALL SILVER DIAGONAL

  • Please log in to reply
214 replies to this topic

#26 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 18229
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 29 February 2016 - 09:06 AM

Did you have a recent observation?


  • Charlespl likes this

#27 RichA

RichA

    Apollo

  • *****
  • Posts: 1011
  • Joined: 03 Jun 2010
  • Loc: Toronto, Canada

Posted 01 March 2016 - 07:02 PM

 

 

So, what are the chances this diagonal will fare better than Lumicon's silvered diagaonals and Meade's MCSO telescopes, both of which saw their silver coatings rot off?

That's the 64,000 dollar question, well maybe the 479 dollar question.  Always looks good up front but what about looong term.

 

 

I believe the vendor is claiming that longevity will be the same as protected aluminum.  They are very well aware of the longevity of Silver using the older protective technologies and processes like the ones you mention.  What they are using now is supposed to overcome all those issues.  So should not be any issues.  Time will be the ultimate teller of the story though.  FWIW, I have zero worries on the issue and am rather enjoying the vibrancy it brings to colors. :D

 

As long as the coating isn't porous, it should keep out the acid and the sulfur that occur in the air in some environments.  The problem with precision diagonals is that they (at least, TeleVue) don't offer repairs, only new mirrors.  Don't know about Baader.


  • Procyon likes this

#28 hallelujah

hallelujah

    Fly Me to the Moon

  • *****
  • Posts: 7255
  • Joined: 14 Jul 2006
  • Loc: North Star over Colorado

Posted 02 March 2016 - 07:28 PM

Bill,

 

Please provide a link for Baader Silver Diagonals & prices.

 

Thanks,

 

Stan



#29 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 40046
  • Joined: 23 Jun 2003
  • Loc: Los Angeles

Posted 02 March 2016 - 07:35 PM

Link to info about Baader diagonals:

http://www.alpineast...r_Diagonals.htm


  • A6Q6 likes this

#30 hwb3

hwb3

    Vostok 1

  • -----
  • Posts: 131
  • Joined: 16 May 2011

Posted 05 March 2016 - 12:44 AM

Bill,

 

Please pardon my ignorance, but why would silver's higher transmission of red have an effect on the reflectance of a mirror? I seemed to have learned that all wavelengths are reflected back from the surface but maybe that was too rudimentary (rereading your article, that notion of reflection is now obviously simplistic).

 

Also, I wonder if this new technology could be used in any flat fold mirror--such as Newtonian secondaries?

 

Fascinating report.

 

Hugh


  • Procyon likes this

#31 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 40046
  • Joined: 23 Jun 2003
  • Loc: Los Angeles

Posted 05 March 2016 - 01:00 AM

Of course it could be used in secondary mirrors, and primaries.

Aluminum is used because it costs less, tarnishes very slowly, and is moderately easy to remove.

Silver isn't a panacea--it does have lower transmission at short wavelengths than aluminum.

Having a flat response into the infrared isn't critical for most scotopic viewing since scotopic vision

is largely blind above 600-650nm.

There are other materials with better spectra of reflection in the visible spectrum but they suffer from either the inability

to be removed from the glass, or quick tarnishing, or the tendency to clump when coating.

Over a hundred years of aluminum-on-glass and it's still the most practical coating.

 

Hugh,

Not all wavelengths are reflected with equal strength. Some are not reflected by the material (at those wavelengths, aluminum is essentially flat black) while, at other wavelengths, reflection is strong.

Aluminum, overcoated with a few layers of transparent dielectrics, can reflect in the visible range with quite high percentages.

Silver has a flatter spectrum of reflectance above about 500nm, but poorer transmission from 400 to 500nm than aluminum.

That would accent the longer wavelengths more with a silver coating, producing stronger reds and oranges, but weaker violets and blues.

Aluminum has a flatter spectrum in the visible 400-700nm range.


Edited by Starman1, 05 March 2016 - 01:02 AM.

  • jrbarnett, Neptune, Procyon and 1 other like this

#32 jrbarnett

jrbarnett

    Eyepiece Hooligan

  • *****
  • Posts: 29893
  • Joined: 28 Feb 2006
  • Loc: Petaluma, CA

Posted 05 March 2016 - 02:07 PM

 

 

 C9.25 Edge HD unit's corrective optics, however, are scarcely an inch inside the rear aperture, and there is no stop.

 

Wow.  That's amazing!  Thanks for the info.

 

I have often toyed of getting a 9.25 to replace my 10" Dob as it is a rarely used instrument and I like the smaller form factor of course.  Would be for DSO only.  From what I read little difference off-axis between the Edge and Non-Edge of the 9.25, so would probably go with the non-Edge anyway.

 

True.  Non-edge avoids the issue of corrector-diagonal contact, and also allows use of Lymaz coolers.

 

But the VB on the rear of the standard unit is small like a C8, so you are looking at either an extension 2" adapter or an SCT-style thread on connector where you lose ease of diagonal rotation, with the standard C9.25.  The rear port on the Edge C9.25 is larger like on the C11 and C14.

 

Trade-offs either way, really, but I'd probably go standard C9.25 or even standard C11 (not much difference is mass or length between the two) were I going to do it over again.  Still the C9.25 is a better match for the EM-200 than a C11 would be, and this way if I take the EM-200, I can easily swap between a large refractor and the C9.25 on a camp-out.  The C11 would require more balance and counterweight fiddling.

 

I'm due for a diagonal refresh I think.  Thanks for the report, Bill.

 

- Jim


  • Procyon likes this

#33 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 40046
  • Joined: 23 Jun 2003
  • Loc: Los Angeles

Posted 05 March 2016 - 02:24 PM

Before you rush out to get a silvered diagonal, you should read this and the Q&A that follows:

http://physics.stack...stead-of-silver


  • StarDust1 and astrophile like this

#34 Dan5209

Dan5209

    Sputnik

  • -----
  • Posts: 45
  • Joined: 11 Mar 2014
  • Loc: Frozen Tundra

Posted 06 March 2016 - 10:42 AM

My apologies if this has been mentioned before but it would be interesting to have a comparison to a straight through view. Also await comparison to the 1.25 T2 prism as that is what is on the Mark V binoviewer?


  • Snippy likes this

#35 S Gazer

S Gazer

    Sputnik

  • -----
  • Posts: 35
  • Joined: 09 Feb 2012
  • Loc: Minneapolis

Posted 06 March 2016 - 11:23 AM

Nice review.

 

I hope the protective coating works well.  I'm always quite concerned about the tarnishing aspect of silver.  



#36 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 18229
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 07 March 2016 - 08:49 AM

Nice review.

 

I hope the protective coating works well.  I'm always quite concerned about the tarnishing aspect of silver.  

 

I am not worried. I've borrowed a Vernonscope Silver that has quite a few years under its belt and no issues.  Also like the way Silver seems to accentuate the views, like on the GRS of Jupiter and heightened colors of stars in clusters.  Makes the observation so much more productive and beautiful.  But even if it only lasts 10-20 years, no big deal as it will be 10-20 years of much better results IMO than can get from any dielectric.  We have high end Silver from Baader and Vernonscope, Aluminum from Tak and probably some others (not sure if TV still makes theirs), and Prisms from Baader and Tak.  Dielectrics I can do without personally.  FWIW no one seems to worry about their Dob mirrors and they never stand the test of time.  :lol:


  • Procyon and StarDust1 like this

#37 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 18229
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 10 March 2016 - 11:33 AM

Before you rush out to get a silvered diagonal, you should read this and the Q&A that follows:

http://physics.stack...stead-of-silver

 

While this discussion is well and good, it is referring to technologies more than 2 years old.  And in today's world that is a lifetime.  FWIW, current manufacturers show reflectance graphs for their protected silver coating that are not what is given in this forum referenced.  As example, Action Optics and Coatings released last year that their enhanced UV coatings for Silver maintains reflectance between approx. 98-99% from 400-900 - http://www.actonopti... Coated Mirrors.  So this is quite different from the dated discussion talking that from 400 nm to 700 nm - silver varies from 80% to 95%

 

So today, there are technologies with Silver that have overcome some of the old no longer relevant issues.  And given that each manufacturer has a process that varies from others, we would really need to know exactly the results are for whichever process Baader uses for the BBHS.  The Baader marketing implies that the reflectance is flat from 400 to 2000 nm.  Have not seen any test data to back that up, but have to say that in use on my scopes the whites are accentuated just as much as the colors are so nicely saturated.  So am quite enjoying the greater vibrancy I am now seeing for blues and reds and also brighter appearing whites (sounds like a laundry detergent line doesn't it :lol: ).


Edited by BillP, 10 March 2016 - 02:12 PM.

  • Procyon and astrophile like this

#38 desertlens

desertlens

    Apollo

  • *****
  • Posts: 1347
  • Joined: 06 Dec 2010
  • Loc: 36°N 105°W

Posted 10 March 2016 - 11:58 AM

Bill, Thanks for the review, very thorough as usual. I've ordered one simply because it's bound to be an improvement over the run of the mill 2" dielectric diagonals I've been using. How significant remains to be seen. Expensive? Yes, but I'm confident that I'll have high quality in the diagonal position of my optical train.

 

Edit: I use Baader 1.25" click-locks on a couple of T-thread diagonals and wholeheartedly agree that they are by far the most convenient EP holder I've ever used. Fast, easy, good centering  and they completely negate any issues with safety undercuts. I'm looking forward to the 2".


Edited by desertlens, 10 March 2016 - 01:07 PM.

  • swetzel likes this

#39 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 40046
  • Joined: 23 Jun 2003
  • Loc: Los Angeles

Posted 10 March 2016 - 03:33 PM

The greater transmission flatness from 500-700nm should enhance the longer wavelengths.

We'll see if the transmission curves match the UV-enhanced silver in the Acton Optics link.


  • Procyon likes this

#40 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 18229
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 10 March 2016 - 04:33 PM

Actually I doubt it.  No one provides independently produced transmission graphs that I've seen for diagonals.  I've seen some vendors supply their own from cherry picked equipment, but it carries no weight unless an independent source can select from random production units.  And of course even that is no good unless they are allowed to do the tests on a large enough population drawn randomly.  Tests of single units do not validate anything other than that particular unit.  Besides, I will trust my eyes over a graph produced on some population of one unit.  I'm quite enjoying the view that Silver provides...even more than my prisms now!  Am able to pick up more subtle colors and color variations am unable to using prisms or dielectrics.

 

Besides, the human eye does not respond to blue well.  Much less sensitive to blue than it is to green and red.  And given the much better response of the red and green cones, means that sensitivity to the mixed colors like yellow, is even higher.  400-625 is really the zone where the sensitivity is above 50%.  And do not think a 1% difference here and there is going to matter all that much as far as changing the appearance of the color. But stranger things have happened.  IMO one should be concerned over this if doing some critical data gathering from sensors.  But for visual?  I don't think it matters.  What is important is which technology is showing me the views the best, and best being subjective.  Having a choice of flatter looking colors from my premium dielectric, or vibrant looking colors from the silver, it is an easy choice.  Of course this is how it appears using my 4" and 6" instruments that utilize the diagonal.  With all the additional light gathering of a 12" Dob, as example, things might change.  But who sells silver primary and secondary mirrors?  Would be an interesting test to compare an all aluminum mirrored Dob to an all silvered one, as well as the dielectric vs silver diagonal on a larger SCT.


Edited by BillP, 10 March 2016 - 04:52 PM.


#41 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 40046
  • Joined: 23 Jun 2003
  • Loc: Los Angeles

Posted 10 March 2016 - 07:04 PM

Scotopic vision has a peak sensitivity at about 507nm, with a roll off above 550 and below 450

Note that 550 is in the green and 450 is in the violet.

http://www.physlink....ages/ae409a.gif

 

For night use, flat from 450 to 550 is important.

But, as has been pointed out many times, having an extended response at long wavelengths does sometimes matter.

Some nebula filters purposely pass the reds, even though our sensitivity is way down at those wavelengths, and it definitely makes seeing reds in nebulae easier.

 

Here is a page detailing "protected silver" (simple overcoating) versus "dielectric coated silver" (multi-layer dielectrics added to silver).

It would be interesting to see which curve the Baader comes closest to, but the simple protected silver is pretty nice on its own.

https://www.layertec...metalDielectric

Similar curves for protected aluminum and "enhanced" aluminum show much more pronounced humps in reflectance.


Edited by Starman1, 10 March 2016 - 07:06 PM.

  • jrbarnett likes this

#42 ybor

ybor

    Messenger

  • -----
  • Posts: 459
  • Joined: 07 Jan 2006

Posted 19 March 2016 - 03:08 PM

Need comparison of BBHS diagonal with the Zeiss 34mm diagonal using 1 1/4 inch eyepieces . Especially for Planetary and lunar high power viewing .

 

 

Thank you 



#43 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 18229
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 19 March 2016 - 08:03 PM

Similar curves for protected aluminum and "enhanced" aluminum show much more pronounced humps in reflectance.

 

These "humps" in the last link are 1% or less.  As everyone here likes to say, human eyes are just not that sensitive to small % changes.  So visually, I would say nothing at all to be concerned about as it is effectively flat.  But the real bottom line is never the graph, and always the performance in the field, in which for me Silver far outshines Dielectrics on several fronts based on my direct observations.  So think I will keep the Silver as a mainstay as it just plain does better  :grin:


  • jrbarnett likes this

#44 hwb3

hwb3

    Vostok 1

  • -----
  • Posts: 131
  • Joined: 16 May 2011

Posted 19 March 2016 - 08:11 PM

Don, thank you for the very thorough reply!


  • jrbarnett likes this

#45 astrophile

astrophile

    Viking 1

  • -----
  • Posts: 577
  • Joined: 30 Jun 2013
  • Loc: NoVA Yellow Zone

Posted 22 March 2016 - 07:33 PM

Looks like these are starting to hit the market in greater numbers... Agena Astro and High Point Scientific now selling them in stock.



#46 Disciplus55

Disciplus55

    Messenger

  • *****
  • Posts: 442
  • Joined: 20 Dec 2014
  • Loc: East of France

Posted 23 March 2016 - 04:55 AM

Indeed, got mine yesterday  :waytogo:



#47 BillP

BillP

    Hubble

  • *****
  • topic starter
  • Posts: 18229
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 23 March 2016 - 12:36 PM

Indeed, got mine yesterday  :waytogo:

 

Outstanding!  Let me know your thoughts once you've had some time with it.



#48 Disciplus55

Disciplus55

    Messenger

  • *****
  • Posts: 442
  • Joined: 20 Dec 2014
  • Loc: East of France

Posted 23 March 2016 - 02:12 PM

Sure, if the clouds dare leaving the area... Weather forecast is not optimistic for the coming days...



#49 bgi

bgi

    Apollo

  • *****
  • Posts: 1383
  • Joined: 01 Dec 2005
  • Loc: Ga

Posted 25 March 2016 - 09:22 AM

I got mine a few weeks ago.  Have to say that the difference the BBHS made for me on Jupiter during a 30 min session was quite astonishing.  Compared to the ES and WO dialectric, colors were improved and scatter reduced.  I switched back and forth several times.  It was similar to dialing the saturation and contrast up and down in a photo editor.

 

I didn't compare to the Baader T2 yet because it doesn't reach focus without an extender (which I didn't have handy at the time).

 

Highly recommended if you're into getting the most out of your refractor on planetary observations.


  • Kunama likes this

#50 TH1

TH1

    Viking 1

  • ****-
  • Posts: 791
  • Joined: 24 Jul 2010
  • Loc: Silicon Valley

Posted 26 March 2016 - 11:57 AM

I've purchased the Lunt 152 after a year thinking about it based ultimately on Bill's excellent review. Now after reading another outstanding contribution by Bill to us here on CN about the BBHS, I purchased it, after selling some items. It sounds like yet another exciting game changer for us like the Lunt was. 

 

I am not as optimistic about the durability of the silver and believe it will fade in 3-4 years or less, but I promise to make the best of this time! Maybe a more durable one by then.

 

I am also wondering about its use for White Light observing and would love to hear about any IR affecting this new mirror.  The baader solar film should block the UV I would hope. 

 

So now I've got a grab and go 6" Apo that can be used visually on an AVX, a Sitall Silver mirror, coupled with a Binotron 27 with the LOAs, 

 

Yep, the next star party could get a little busy around my place.


Edited by TH1, 26 March 2016 - 11:58 AM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics